Move kMinPixelsPerFrame constant in VideoStreamEncoder to VideoEncoder::ScalingSettings.

webrtc/modules/video_coding/codecs/vp8/vp8_impl.h

 /*
  *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  *
  * WEBRTC VP8 wrapper interface
@@ skipping 76 matching lines @@
 
   int GetEncodedPartitions(const TemporalLayers::FrameConfig tl_configs[],
                            const VideoFrame& input_image);
 
   // Set the stream state for stream |stream_idx|.
   void SetStreamState(bool send_stream, int stream_idx);
 
   uint32_t MaxIntraTarget(uint32_t optimal_buffer_size);
 
   const bool use_gf_boost_;
+  const rtc::Optional<int> min_pixels_per_frame_;
 
   EncodedImageCallback* encoded_complete_callback_;
   VideoCodec codec_;
   bool inited_;
   int64_t timestamp_;
   int qp_max_;
   int cpu_speed_default_;
   int number_of_cores_;
   uint32_t rc_max_intra_target_;
   std::vector<std::unique_ptr<TemporalLayers>> temporal_layers_;
@@ skipping 50 matching lines @@
   int propagation_cnt_;
   int last_frame_width_;
   int last_frame_height_;
   bool key_frame_required_;
   DeblockParams deblock_;
   const std::unique_ptr<QpSmoother> qp_smoother_;
 };
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_VIDEO_CODING_CODECS_VP8_VP8_IMPL_H_